Originally Posted by DataJunkie
Like many wool makes me itch.
One cheaper merino wool jersey still makes me itch a bit. Smartwool does not.
I would assume it to be the difference in quality between the two.
Many people have issues with wool products.
1. Some commercially produced wools are from nasty fleeces that are full of plant fibers. The manufacturer uses chemicals to dissolve the plant fibers but keep the wool. Some people are sensitive to this.
2. Smartwool has a "superwash" treatment applied to it. This alters the wool fibers so there are no "hooks", and thus it can't felt any more. Some people are sensitive to the "hooks" and when they're removed, they find the wool isn't itchy anymore. (there at least two superwash treatments that I know of, and there is at least one breed of wool that is naturally superwash...) I'm also aware of some people who react to the superwash treatment. So this one can go either way.
3. Most commercial hand-knitting yarn (and at least some machine knitting yarn) has a permanent mothproofing treatment applied to it. This can give people reactions.
4. Some people are very sensitive to fiber diameter or fiber texture. Since wool is a natural fiber, the fiber diameter and texture varies. If you're one of the sensitive types, you will notice this.
5. Some people have an actual reaction to wool itself. Pretty rare.
6. Some people have an actual reaction to lanolin (a moisturizing agent that sheep produce, and that is left in some kinds of wool yarn). Fairly common. If you also react badly to a wide variety of hand lotions, this may be your problem.
7. Some people are very suggestible, and since common wisdom says "wool is itchy"... they find it itchy. (this was me for a long time)
8. A wool that is otherwise ok can be spun firmly so that it feels coarse. Some folks find this itchy. (this is so me sometimes)
I'm sure there are other reasons why one might find a given wool itchy... these are just the ones I can think of off the top of my head as a handspinner. And of course any given person can have more than one affecting them. If you're *quite* sure that #5 isn't the problem, it can be enlightening to poke at the itching judiciously. There's a whole lot of personal taste involved.
(and yes, I use lots of thrifted wool sweaters as a keep warm layer. hard to spin and knit fast enough to keep myself in sweaters